U.S. President Barack Obama says the losses in Haiti are nothing "less than devastating."

At the White House Thursday, the president announced a $100 million investment to support American relief efforts. He said U.S. support has arrived in the Caribbean nation and more is on its way. He said it will take hours, maybe days, for all of the U.S. resources and personnel to arrive. He said the United States stands in solidarity with Haiti.

The United States has launched a major civilian and military response to the massive earthquake in Haiti that devastated the capital, Port-au-Prince.

Soldiers from the 82nd Airborne Division will leave from a military base in the southern U.S. state of North Carolina Thursday to begin preparing for the arrival of a larger force. More than 2,000 Marines are traveling to the area to help with security needs, search and rescue and the delivery of humanitarian supplies.

Former U.S. President Bill Clinton, the United Nations special envoy for Haiti, says the earthquake is one of the greatest humanitarian emergencies in the history of the Americas.

Mr. Obama has promised Haiti the full support of the U.S. in rescuing people and delivering humanitarian relief.

Secretary of State Hillary Clinton and Defense Secretary Robert Gates canceled trips to the Asia-Pacific region to help oversee relief efforts for Haiti from Washington.

The head of the U.S. Agency for International Development, Dr. Rajiv Shah, says the U.S. disaster assistance response teams include personnel, search and rescue dogs, and up to 48 tons of rescue equipment.

The State Department says it is aware of at least three possible American deaths, and says it is working to locate U.S. embassy personnel and other U.S. citizens in Haiti. Americans trying to reach missing relatives in Haiti can call the State Department at 1-888-407-4747 or 202-647-5225.

U.S. citizens in Haiti can call the Embassy's Consular Task Force: 509-2229-8942, 509-2229-8089, 509-2229-8322, or 509-2229-8672.